FOUL PLAY: Amar'e Stoudemire is whistled as he runs into the Spurs' DeJuan Blair during the Knicks' 101-92 loss last night in San Antonio. AP

SAN ANTONIO — A deal with the Nuggets appears to be, according to one source familiar with the situation, “problematic.” But Knicks president Donnie Walsh still has a backup plan — hoping Carmelo Anthony becomes a free agent, and the two teams working on a sign-and-trade during the summer.

A 1050 ESPN New York report stated the Knicks have been rejected by Denver on an offer this week of Wilson Chandler, rookie Landry Fields and a first-round pick the Knicks presumably can obtain for Anthony Randolph. If the report has merit, Eddy Curry’s expiring contract would have been included in the package.

“Donnie doesn’t want to give up five pieces in this,” one source said.

Chandler was demoted from the starting lineup for last night’s 101-92 loss to the Spurs and the conspiracy theorists say it’s a precursor to his Knicks exit in an Anthony trade. Knicks coach Mike D’Antoni said the demotion could be permanent, and creates uncertainty about Chandler’s future one week after he fired his agent, Chris Luchey, and just two weeks after Walsh told The Post he planned to sign Chandler this summer.

However, a looming Denver deal won’t be easy. Walsh sits in the driver’s seat as long as the Nets stay out of it.

The Knicks were heartened by candid remarks from Warriors owner Joe Lacob to the San Jose Mercury News, in which Lackob said he has spoken to Denver and was told Anthony would not sign an extension there, with Nuggets brass telling him, “He clearly wants to be one place geographically.”

If Denver’s only option is dealing him elsewhere as a rental, that benefits the Knicks greatly because he’ll still be free this summer. Denver also has the option of rolling the dice, not dealing him and hoping he re-signs or wheels him in a sign-and-trade.

According to a source, the Players Association hopes Anthony does not make his decision based on a doomsday scenario NBA commissioner David Stern and his agents are promoting. The union hopes Anthony goes about his business as normal, knowing NBPA executive director Billy Hunter will not agree to an unfavorable CBA deal for its superstars.

Walsh may not be pleased about the news Chandler had fired Luchey and was looking elsewhere. Walsh and Luchey had extended talks regarding a contract extension in late October, and there was a sense Walsh felt comfortable with Luchey.

Regarding his name being mentioned yesterday in an Anthony deal, Chandler said, “I’m happy here. I don’t think about it. It’s the nature of the NBA. If it happens, it’s going to happen. You have to go out and play and not worry about it.”